The present invention relates to a system for injecting a fluid, such as water or a water solution, into a turbocharged internal combustion engine.
Various cooling fluids, such as water and water in solution with other substances, such as methanol or alcohol, have been commonly injected into hydrocarbon engines, both of the spark-ignition and compression-ignition type, to provide improved engine operation. These improvements are possible since, during the compression stroke of the engine, the water droplets evaporate and thus absorb heat and prevent pre-ignition. On the power stroke the gasoline is burned and the remaining water is turned to steam which absorbs more heat and helps prevent detonation and the formation of nitrous oxides. Also, as the water turns to steam, it undergoes considerable expansion which produces significant additional power. Further, as a result of the above, combustion occurs at lower temperatures and is more even, and the pistons and valves enjoy a longer life. Further, the presence of water also creates a "steam cleaning" process that tends to remove carbon and other deposits from the combustion chamber, as well as prevent the formation of additional deposits.
Various types of prior devices have been used to introduce cooling fluids into internal combustion engines. These devices have included nozzle-type injectors in which the fluid is pumped directly into the engine and intake air humidifiers in which air is passed through a volume of water before being introduced into the engine. However, since the injection of a relatively low volume of fluid is desired when compared to the volume of fuel introduced into the engine, it is difficult, if not impossible, to meter the fluid with the precision needed to insure optimum performance when it is pumped directly into the engine. Also, if humidified air is used, there is a reduction in power and fuel economy since the humidified air is less dense than dry air with water droplets. Also, the use of humidified air does not permit the cooling effect caused by the evaporation of the water droplets.
The use of turbocharged engines has further high-lighted the advantages of injecting cooling fluids into the engine since, for example, the high volume of air being processed in a turbocharged engine increases the temperature and therefore increases the possibility of detonation in the engine. However, the aforementioned prior art technique of pumping a stream of unatomized water directly into the carburetor, and therefore into the turbocharger, is unsatifactory since the relatively heavy unatomized water impinges on the impeller blades and causes corrosion and premature failure of the blades.